package com.tongtech.space.common.handler;

import com.baomidou.mybatisplus.core.metadata.IPage;
import com.tongtech.space.common.pojo.Result;
import org.springframework.core.MethodParameter;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.web.bind.annotation.RestControllerAdvice;
import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice;

import java.util.Collection;

/**
 * 全局接口返回数据格式设置
 *
 * @author jinjiayu
 * @since 2020/12/14
 */
@RestControllerAdvice("com.tongtech.space.controller")
public class GlobalApiReturnHandler implements ResponseBodyAdvice<Object> {

    /**
     * Whether this component supports the given controller method return type
     * and the selected {@code HttpMessageConverter} type.
     *
     * @param returnType    the return type
     * @param converterType the selected converter type
     * @return {@code true} if {@link #beforeBodyWrite} should be invoked;
     * {@code false} otherwise
     */
    @Override
    public boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {
        return true;
    }

    /**
     * Invoked after an {@code HttpMessageConverter} is selected and just before
     * its write method is invoked.
     *
     * @param body                  the body to be written
     * @param returnType            the return type of the controller method
     * @param selectedContentType   the content type selected through content negotiation
     * @param selectedConverterType the converter type selected to write to the response
     * @param request               the current request
     * @param response              the current response
     * @return the body that was passed in or a modified (possibly new) instance
     */
    @Override
    public Object beforeBodyWrite(Object body,
                                  MethodParameter returnType,
                                  MediaType selectedContentType, Class<? extends HttpMessageConverter<?>> selectedConverterType,
                                  ServerHttpRequest request,
                                  ServerHttpResponse response) {

        if (body == null) {
            return Result.success(null, 0);
        }
        if (body instanceof String) {
            response.getHeaders().setContentType(MediaType.APPLICATION_JSON);
            return Result.successSingle(body);
        }
        if (body instanceof Result) {
            return body;
        }
        if (body instanceof IPage) {
            IPage<?> page = (IPage<?>) body;
            return Result.success(page.getRecords(), page.getTotal());
        }
        if (body instanceof Collection) {
            return Result.success(body, ((Collection<?>) body).size());
        }
        return Result.success(body, 1);
    }
}